Examine source code of Minimal Twitter

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Minimal Twitter",
  "short_name": "MinTwitter",
  "description": "A minimal twitter theme for the new Twitter!",
  "version": "1.0",
  "manifest_version": 2,
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "css": [
        "minimal-twitter.css"
      ],
      "matches": [
        "https://twitter.com/*"
      ]
    },
    {
      "js": [
        "removePromoted.js"
      ],
      "matches": [
        "https://twitter.com/home"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "images/MinimalTwitterIcon16.png",
      "32": "images/MinimalTwitterIcon32.png",
      "48": "images/MinimalTwitterIcon48.png",
      "128": "images/MinimalTwitterIcon128.png"
    }
  },
  "icons": {
    "16": "images/MinimalTwitterIcon16.png",
    "32": "images/MinimalTwitterIcon32.png",
    "48": "images/MinimalTwitterIcon48.png",
    "128": "images/MinimalTwitterIcon128.png"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+T",
        "mac": "MacCtrl+Shift+T"
      },
      "description": "Opens Minimal Twitter"
    }
  }
}